The governor said he took his cue from previous federal court rulings that found that nothing in New Jersey law prohibits the casinos and horse racing tracks from offering sports betting, so long as it's not sponsored or licensed by the state. Besides issuing the directive, he asked a federal court to approve it.

His action, through the state attorney general's office, is likely to be challenged by the professional and collegiate sports leagues that fought New Jersey's efforts to overturn a ban on sports betting in all but four states. That effort ended with the U.S. Supreme Court declining to hear the case.

Christie suggested casinos and tracks could start offering betting immediately, but it's not clear that will happen. Rachel Ryan, a spokeswoman for the Meadowlands Racetrack said Monday that the track has no plans to offer sports betting now. Several casino executives ether said they have no immediate plans to offer it or declined to comment.

The professional football, baseball, basketball and hockey leagues, as well as the National Collegiate Athletic Association, all opposed New Jersey's effort to legalize sports betting, saying it could give the appearance that the integrity of the games has been compromised. An NFL spokesman declined comment; the other leagues and the NCAA did not immediately return messages Monday.

In addition to the directive, Christie also had the state file a motion in federal court asking a judge to clarify or modify a February 2013 ruling that blocks a licensing program New Jersey had passed for sports betting in the state.

The governor says sports betting is legal under previous federal rulings as long as wagers don't involve a collegiate game played in New Jersey or a New Jersey college team elsewhere in the country.

"Victory at last!" said state Sen. Raymond Lesniak, one of the legislature's strongest supporters of sports betting. "People should book their hotel rooms in Atlantic City for the Super Bowl now because there won't be any available in February."

Lesniak said he expects the leagues to challenge the move, but predicted: "They don't have any arguments left to make. This is all over but the shouting."

Lloyd D. Levenson, an Atlantic City lawyer whose firm works for casinos in New Jersey and elsewhere, said he expects the casinos to wait for a further court ruling before they launch sports betting but that they'll begin setting up an infrastructure for it now.

The move is a turnaround for Christie, who supported allowing sports gambling previously. But he initially seemed resigned to defeat once the U.S. Supreme Court declined to hear New Jersey's appeal in June, saying, "You know, that's the way it goes."

A month ago, Christie vetoed a bill that would have pushed New Jersey to circumvent the federal ban on gambling on professional and college sports.

Later Monday, Christie convened a closed-door summit on the future of Atlantic City. The seaside resort has already lost three of the 12 casinos with which it began this year, and a fourth one is due to shut its doors next week; about 8,000 casino workers will have lost their jobs since January.

"It is never easy to go through the type of displacement we're going through now," he told the panel, which included executives from the Tropicana, Golden Nugget, Resorts and Borgata casinos.

Voters in New Jersey overwhelmingly endorsed legal sports betting in a nonbinding referendum in 2011. State lawmakers soon enacted a law to allow for betting at tracks and in casinos. But those actions ran up against the 1992 Professional and Amateur Sports Protection Act, enacted by Congress to restrict betting on sports to a few states. Nevada has allowed betting on sports for more than 60 years, and Delaware, Montana and Oregon have at times permitted more limited betting. New Jersey missed a 1991 deadline in the law that would have allowed sports betting in Atlantic City.